These are proceedings by the firm of solicitors Hughmans against Alexandra Dunhill for payment of fees amounting to £179,666.68 and interest. Ms Dunhill has counterclaimed for, among other things, damages for negligence in breach of the contract of retainer and in breach of duty of care, damages for misrepresentation, and compensation for breach of fiduciary duty.

Ms Dunhill has applied to amend her Defence and Counterclaim by, among other things, adding as a counterclaimant her son W, who is 16 years of age and who she intends to represent as his litigation friend. It is common ground that she is also able to advance any claims against Hughmans that her adult children, Natasha and Piers, may have and which they have assigned to her.

This is an appeal by Ms Dunhill against the order of Mr Justice Arnold dated 11 May 2015 which, among other things, gave summary judgment for £187,593.26 (including interest) on Hughmans' claim, dismissed Ms Dunhill's application for summary judgment on seven issues relevant to the Defence and Counterclaim, gave summary judgment for Hughmans dismissing the counterclaim, and dismissed Ms Dunhill's application to amend the Defence and Counterclaim.

The facts, and the issues in the court below, are fully set out in the lengthy and detailed judgment of the Judge: [2015] EWHC 716 (Ch).

We allow the appeal against the Judge's order insofar as it gave summary judgment in favour of Hughmans on the Claim and the Counterclaim and refused Ms Dunhill's application to amend the Defence and Counterclaim. We dismiss the appeal against the Judge's order dismissing Ms Dunhill's application for summary judgment.

Hughmans' application for summary judgment

The Defence and Counterclaim run to 58 pages and 130 paragraphs. The proposed amended Defence and Counterclaim run to 72 pages and 147 paragraphs. The hearing before the Judge lasted more than three and a half days. The appeal before us lasted one and a half days. The Judge's judgment is a model of clarity and conscientiousness and he correctly cited the applicable principles summarised by Lewison J in Easyair Ltd v Opal Telecom Ltd [2009] EWHC 339 (Ch) at [15]. Contrary to those principles, however, he conducted a mini-trial in reaching conclusions on matters central to the success of the Defence and Counterclaim, which have a real prospect of success if allowed to proceed to a trial following disclosure and with the...